The stand-your-ground doctrine, which has vaulted into national prominence with the killing of Florida teenager Trayvon Martin, isn't limited to the two dozen states that have passed laws since 2005 expanding the right to use deadly force in confrontations.

It's also the rule in California, by court decree. For more than a century, the state's judges have declared that a person who reasonably believes he or she faces serious injury or death from an assailant does not have to back off - inside or outside the home - and instead can use whatever force is needed to eliminate the danger.

The California Legislature has never enacted one of the National Rifle Association-sponsored laws, pioneered by Florida in 2005, that spell out the rights of a defendant in such confrontations and the procedures for applying them in court. But in California, the judicial rulings had much the same effect. The rulings are binding on state courts and are reflected in judges' instructions to juries in cases involving claims of self-defense.

The instructions say a person under attack is even entitled, "if reasonably necessary, to pursue an assailant until the danger of death or great bodily injury has passed. This is so even if safety could have been achieved by retreating."

Most states had similar rules until 30 or 40 years ago, when some passed laws barring a claim of self-defense outside the home if the person could have fled safely, said Andrea Roth, a UC Berkeley law professor. She said almost all states still allow the use of deadly force against home intruders.

"California's law perpetuates the old frontier rule," she said. "This is not some new brainchild of the NRA."

The Florida law, however, contains a major pro-defense feature absent in California and other states: a pretrial, nonjury hearing in which a judge, after considering the evidence, decides whether it's more likely than not that the defendant acted in self-defense.